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MDP

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Joined: 2010-08-07

Posted: February 15, 2014 - 11:56pm

Hope this is the right forum! Looking at the data, said Supernova seems to be fluctuating over brief(one or two days)periods. I noticed a similar pattern with Nova Del last year. Am I "seeing things" or does the data reflect an up and down rhythm?If so what might causing it?

If you look at the visual dots,as well as the Green and Blue ones, around Feb 2nd, for example, there seems to be a short term rise followed by a return to baseline. Around Feb 6th and 8th there appear to be dips in both the green and visual dots. It seems too well defined to me to be just random scatter. It reminds me of the dips we look for in the Planet Hunters Zoouniverse project-not that it is caused by planets of course, but that it is a distinguishable pattern in the data.

Don't read too much into SNe light curves! Remember that you are dealing with a dozen different observers using different techniques, filters, etc. I see one observer using a DSLR (TG, anyway), where two nights around Feb 8 have nice long time series, but with exactly identical structure. Anything that has a 1.000 day feature should be suspicious.

The variation in the digital photometry is pretty typical, and shows the differences between observers when data is not transformed or the same comp stars are not used. The same goes for visual observers - there is always a band about 0.5mag wide, showing the differences between observers, and the eye can find patterns pretty easily. To trust that any pattern is real takes a lot more work.

That said, looking at light curves carefully is a Good Thing; you can often catch some obviously discrepant observations and report them via Zapper; you can find patterns that can be confirmed by specific follow-up observations that might have astrophysical significance.